feat: add admin profile editing capability

Added admin endpoint and functionality for editing user profiles from the
report management interface:

Backend Changes:
- Added PUT /api/users/:id endpoint for admin-only profile editing
- Reuses existing updateUserSettings logic with slug uniqueness validation
- Protected with adminGuard and csrfProtection
- Proper audit logging for admin profile edits

Frontend Changes:
- Added adminUpdateUser() method to UserService
- Updated editProfile() in admin-reports to load profile and allow bio editing
- Uses prompt for quick bio editing (can be expanded to full form later)
- Shows success/error toasts and refreshes report list after edit

Admins can now quickly edit reported user profiles directly from the
report management interface.

api/src/app/routes/users/index.ts

@@ -255,6 +255,40 @@ const usersRoutes: FastifyPluginAsync = async (app) => {
       return user;
     }
   );
+
+  app.put<{ Params: { id: string }; Body: UpdateUserSettingsBody; Reply: User | { error: string } }>(
+    "/:id",
+    {
+      preValidation: [app.authenticate, adminGuard],
+      preHandler: [app.csrfProtection],
+    },
+    async (request, reply) => {
+      const { id } = request.params;
+      const updates = request.body;
+
+      // If slug is being updated, check if it's unique
+      if (updates.slug) {
+        const existingUser = await userService.getUserBySlug(updates.slug);
+        if (existingUser && existingUser.id !== id) {
+          return reply.code(400).send({ error: "Slug already taken" });
+        }
+      }
+
+      const updatedUser = await userService.updateUserSettings(id, updates);
+      if (!updatedUser) {
+        return reply.code(404).send({ error: "User not found" });
+      }
+
+      await AuditService.logFromRequest(request, {
+        action: AuditAction.entryUpdate,
+        category: AuditCategory.admin,
+        targetUserId: id,
+        details: `Admin updated profile for user: ${updatedUser.username}`,
+      });
+
+      return updatedUser;
+    }
+  );
 };
 
 export default usersRoutes;